At present, there is an ever increasing need for machinery that can handle mixed mail, envelopes, and other varying sheet-like material at high speed. Heretofore, machinery designed to process large amounts of mixed mail at high speed has been always limited to a narrow range of envelope thicknesses and sizes. This was due to the fact that there is no known separators and feeders that can automatically deliver separated mixed sheet outside of a very limited range. Separators that are adjustable for thicker sheet will not function properly for thinner materials and vice versa. Therefore, if a wide range of material is fed into these devices, double feeds, jams, and other unacceptable conditions, will result. Clearly, there exists a need for an automatic (no adjustment) separating and feeding system that will provide a high speed steady stream of mixed material. The present invention addresses itself to this requirement.